Ordering a 3500 but which transmission?

[Phil3500]

I'm towing a 39 ft fifth wheel that weighs in at 18,000 lbs with a pin weight of about 3800 lbs. I've decided based on numbers that the 3500 will do with the 6.7L diesel. The question is which transmission of the three offered provides the best towing for this weight. (The dealership salesmen look at men like I've just landed from Mars when I ask) The transmissions are:
1. 8-spd auto 8HP75-LCV
2. 6-spd auto 65RFE
3. AISIN 6-spd auto

All three are zero dollar additions to the build. Thanks for your input!

 

[Gamedog]

I'd go Aisin on the 3500 and not think twice about it.

 

[star_deceiver]

The 8hp75 is for the Hemi only.

I have no love for any RFE transmission.

The Aisin shifts slow and deliberate and will probably drive you nuts unloaded but is good with heavy loads.

 

[Sandevino]

My preference would be the 8HP75-LCV as you’ve got a bulletproof transmission.

You want the Cummins so you’ve only got two choices, 68RFE or the Aisin.

If it were me, go with the H.O. Cummins and the AISIN.

 

[smurfs_of_war]

65RFE or 68RFE?

Correct me if I am wrong, but I thought the service intervals on the Aisin were much shorter than the RFE? I might gravitate to the RFE (if it's a 68RFE) simply because I'd never have need for the PTO capability and it should have no problems with the weight you're likely going to have out back.

I know that makes me the odd man out, but I tend to follow the 'less is sometimes more' mantra.

 

[Walter Conrad]

The 8 speed is only available with the 6.4 Hemi.
the 68RFE is available with the standard 6.7 Cummins
and the Aisin is only available with the HO 6.7 Cummins.

With the weight you are claiming to be towing the standard 370 hp 850 lb.ft. torque 6.7 with a 4.10 axle and 68RFE trans will be more than adequate and would be good through about 23,000lb trailer weight
JMHO the HO/Aisin set up is a bit of overkill for around town driving, the Aisin shift mapping is clunky when unloaded, you will loose about 700 lbs. in cargo capacity and it is an extra $3000.00 option that could be used for other optional equipment

 

[392DevilDog]

As mentioned you don't really get a transmission choice.

You get 3 engine choices each mated to a different transmission.

So your 1 2 3 would read

1. 6.4l HEMI
2. 6.7L CUMMINS SO
3. 6.7L CUMMINS HO

Since you already decided on a Cummins...you have to decide SO or HO.

As stated the HO is for truly large loads or bragging rights.

SO has done just fine with the load you want to pull. And is a bit tamer when that truck isn't hooked up to a trailer.

But, the decision is yours

 

[Phil3500]

Thanks for all the inputs. I should have stated that I wanted the Cummins SO. I was confused by the online build configurator as it allows me to mate the SO engine with any transmission at no additional cost. Sounds like the best pairing for me is the 68RFE. It's less of a beast when not towing and longer service intervals.

Edit: I went back to the configurator and found that the only transmission it allows with the SO is the 68RFE. Turns out, if you pick another transmission it changes your engine without telling you.

 

[RandomRam]

With that much weight you are well into dual rear wheel territory and should absolutely go Aisin.

 

[Huskerz1]

I'm towing a 39 ft fifth wheel that weighs in at 18,000 lbs with a pin weight of about 3800 lbs. I've decided based on numbers that the 3500 will do with the 6.7L diesel. The question is which transmission of the three offered provides the best towing for this weight. (The dealership salesmen look at men like I've just landed from Mars when I ask) The transmissions are:
1. 8-spd auto 8HP75-LCV
2. 6-spd auto 65RFE
3. AISIN 6-spd auto

All three are zero dollar additions to the build. Thanks for your input!

Definitely in Dually territory with that beginning payload number on pin weight. I faced the same decision regarding Aisin vs 68RFE. I pull a 13.5K 39 ft 5th wheel that I used an 07.5 Mega Cab Cummins with a 68RFE for 14 years to do it. Did just fine and now I have 200 ft lbs of more torque to do it with the SO engine. While shopping around I test drove both the 2020 3500 dually Aisin and the 68RFE. I suggest you do the same. Two very different experiences unloaded. One has better around town driving manners than the other. I think with your load you could go either way and be fine. if you choose the 68RFE, I'd pair it with 4:10 gears in your case. I ordered my truck back on May 6th and it arrived June 22nd fyi. The 2020 order banks close soon I believe.

 

[392DevilDog]

Using the build configurator 2 other things will change automatically.

If you choose 4.10 gears...you will default to a dually. Or if you choose them it could also default to the Hemi.

4.10 gears is only available on 3500 dually with the diesel.

If you are shopping 2500...4.10 is only available on a Hemi

 

[mtnrider]

4:10 is a pretty low gear for the cummins, I would only want it if my truck was a heavy tow pig only (aka dually). 3.73 is the sweet spot in my opinion.

OP, I have had no issues with my 68RFE and think its a good transmission. Pretty much all of the problems I have seen with it are with those guys that have tuned the truck. In stock forum it's pretty reliable.


.

 

[Walter Conrad]

The 8 speed is only available with the 6.4 Hemi.
the 68RFE is available with the standard 6.7 Cummins
and the Aisin is only available with the HO 6.7 Cummins.

With the weight you are claiming to be towing the standard 370 hp 850 lb.ft. torque 6.7 with a 4.10 axle and 68RFE trans will be more than adequate and would be good through about 23,000lb trailer weight
JMHO the HO/Aisin set up is a bit of overkill for around town driving, the Aisin shift mapping is clunky when unloaded, you will loose about 700 lbs. in cargo capacity and it is an extra $3000.00 option that could be used for other optional equipment

Just an update to my previous statement
IMHO Both the SO and HO versions of the Cummins engine and it's respective transmissions will preform
the job required by the OP, however the HO/Aisin version will definitely have a higher tow rating
and I believe it will also require and extra measure of chest thumping

 

[John Jensen]

I didn't hesitate, went straight for the HO and Aisin on my 2020 3500. I can't comment on the 68RFE because I never drove one. But I can say the Aisin has not been the dog for my daily, empty driving that others say it is. The 68RFE has had its problems, the Aisin has none. The tuners call the 68RFE a standard transmission, the Aisin a "built" transmission that can handle much more power, the 68RFE cannot unless it is modified. The reason Ram won't couple the 68RFE to the HO is it can't handle it.

I'm a fan of get the best, not what's adequate. It's overkill for me but what you get for the cost IMO is absolutely worth it.

Don't misunderstand me, the 68RFE is a good tranny, the Aisin can just handle so much more and has been trouble free.

 

[Huskerz1]

4:10 is a pretty low gear for the cummins, I would only want it if my truck was a heavy tow pig only (aka dually). 3.73 is the sweet spot in my opinion.

OP, I have had no issues with my 68RFE and think its a good transmission. Pretty much all of the problems I have seen with it are with those guys that have tuned the truck. In stock forum it's pretty reliable.


.

I personally did not opt for the 4.10 gear ratio in my dually. I stayed with the standard 3.73's. My first pull with the 13.5k 5th wheel was great. The SO engine has plenty of power. A lot more than what I was ever used to even coming from a tuned 07.5 6.7L Cummins with a stock 68RFE that gave me zero trouble. OP has about 5k more to tug around than I do. Personally I would have opted for 4.10's if I were over 20k, especially if I were doing more hill and mountain pulling. I'm mostly flat land pulling with the occasional hill climbs.

 

[Huskerz1]

I didn't hesitate, went straight for the HO and Aisin on my 2020 3500. I can't comment on the 68RFE because I never drove one. But I can say the Aisin has not been the dog for my daily, empty driving that others say it is. The 68RFE has had its problems, the Aisin has none. The tuners call the 68RFE a standard transmission, the Aisin a "built" transmission that can handle much more power, the 68RFE cannot unless it is modified. The reason Ram won't couple the 68RFE to the HO is it can't handle it.

I'm a fan of get the best, not what's adequate. It's overkill for me but what you get for the cost IMO is absolutely worth it.

Don't misunderstand me, the 68RFE is a good tranny, the Aisin can just handle so much more and has been trouble free.

I went into the process thinking that same thing. I don't spare money at this price point. It all changed after the test drives. So I did order the best. For me.

 

[Phil3500]

Asked the dealer today to price out the following:

2020 Ram 3500 Crew Cab 6'4" box, SRW
Laramie Longhorn
6.7 L SO engine w/68RFE
4.10 gear ratio
Longhorn Level 1 equipment group
5th Wheel prep

I really don't want to go with the duelly unless I am forced to. I have driven both and the duelly is more difficult to maneuver and rides a little rougher. I'll probably use this truck more without the trailer, so I don't want it to be a "tow pig" as some have described it. The SRW is rated to pull over 20K and has a payload of 3950 in this configuration. Both numbers are within my 5th wheel requirements of 18,000 and 3800.

 

[mtnrider]

Asked the dealer today to price out the following:

2020 Ram 3500 Crew Cab 6'4" box, SRW
Laramie Longhorn
6.7 L SO engine w/68RFE
4.10 gear ratio
Longhorn Level 1 equipment group
5th Wheel prep

I really don't want to go with the duelly unless I am forced to. I have driven both and the duelly is more difficult to maneuver and rides a little rougher. I'll probably use this truck more without the trailer, so I don't want it to be a "tow pig" as some have described it. The SRW is rated to pull over 20K and has a payload of 3950 in this configuration. Both numbers are within my 5th wheel requirements of 18,000 and 3800.

Is your 3800 payload requirement account for everything? Trailer, passengers, luggage, coolers, all that stuff? You are pushing the payload limits of that SRW truck for sure. Of course it can pull that weight but stability would be my concern.

If it were me I would seriously be considering a dually (yes I know they can be pain to drive around). I always like to have some margin if possible and not be right at the max. Guess it depends on how much and far you plan on towing also.



.

 

[392DevilDog]

Asked the dealer today to price out the following:

2020 Ram 3500 Crew Cab 6'4" box, SRW
Laramie Longhorn
6.7 L SO engine w/68RFE
4.10 gear ratio
Longhorn Level 1 equipment group
5th Wheel prep

I really don't want to go with the duelly unless I am forced to. I have driven both and the duelly is more difficult to maneuver and rides a little rougher. I'll probably use this truck more without the trailer, so I don't want it to be a "tow pig" as some have described it. The SRW is rated to pull over 20K and has a payload of 3950 in this configuration. Both numbers are within my 5th wheel requirements of 18,000 and 3800.

4.10 is only available with the dually, as I stated above, unless I missed a change for 2020 which I doubt

 

[Walter Conrad]

Asked the dealer today to price out the following:

2020 Ram 3500 Crew Cab 6'4" box, SRW
Laramie Longhorn
6.7 L SO engine w/68RFE
4.10 gear ratio
Longhorn Level 1 equipment group
5th Wheel prep

I really don't want to go with the duelly unless I am forced to. I have driven both and the duelly is more difficult to maneuver and rides a little rougher. I'll probably use this truck more without the trailer, so I don't want it to be a "tow pig" as some have described it. The SRW is rated to pull over 20K and has a payload of 3950 in this configuration. Both numbers are within my 5th wheel requirements of 18,000 and 3800.

First I don't think you can get a 4.10 axle in a SRW 3500.
Second Your original post you claimed a 3800 lb. pin weight, if that is correct your short box SRW you are pricing will be over it's rated cargo capacity by the time you are all done.
A decent slider hitch will be around 200lbs, A Demco or Pull Right auto slide is in the 400-500lb range then you have passengers and other cargo to consider. If you don't put some kind of slider in you will surly crush the rear of the cab on a tight turn because of the 6'4" bed. If you are going with an Anderson at 3800lb pin you are an accident looking for a place to happen, while they do save a bunch of weight you are extremely close to it's max pin weight plus you will still be over your cargo capacity.
If you are serious about this an 8' bed dually is the only body configuration to consider. I am talking from 20 years of experience hauling a 5th wheel trailer around the United States.
Ultimately it is still your decision and wallet.